Level Blueprint can be reparented to None, crashes Editor on Compile

UE - Gameplay - Blueprint Compiler - Jan 3, 2023

This is a Regression. Tested in //UE5/Release-5.0 CL 20979098 - "None" is not an option for the parent class and the "Reset this Property" is not initially there. ...

Toggling visibility of Sublevels on a server can cause a disconnect if Dynamic Actors exist in the sublevels.

UE - Networking - Aug 17, 2018

The PackageMap / NetGuidCache appear to get into a bad state on Clients if the Server toggles level visibility of a sublevel. This can affect currently connected clients, as well as clients that jo ...

Enabling Strip Source Data On Cook on Geometry Collection is also stripping the Anchor flag of cooked assets

UE - Simulation - Physics - Jul 20, 2025

Enabling Strip Source Data On Cook on Geometry Collection (GC) is also stripping the Anchor flag of cooked assets. The licensee has reported that once they do a build the Anchors disappear and GCs t ...

Spherecast against complex geometry is returning odd results

UE - Simulation - Physics - Sep 19, 2023

Turning on batching of sphere casts when colliding against complex gives incorrect results. Affects debug output and vehicle wheels and body movement. The issue is with the batch query mode which ...

Starting position of physics simulated bp is different in Standalone Game

UE - Simulation - Physics - Feb 26, 2016

Starting position of physics simulated bp is different in Standalone Game User Description: Things work fine in the editor window, but when I run a standalone game then blueprints with physics bod ...

Tick functions are skipped on the first frame in package build and standalone PIE

UE - Gameplay - May 19, 2025

It's reported that all Tick functions are skipped on the first frame when running in packaged builds and standalone PIE. This is because both TickVisitedGFrameCounter and GFrameCounter are initializ ...

Starter Content's "P_Explosion" does not successfully convert to a Niagara System - incorrect loop, spawn, sprite size, and collision behaviors

UE - Niagara - Cascade - Mar 17, 2022

Starter Content's "P_Explosion" does not successfully convert to a Niagara System - incorrect loop, spawn, sprite size, and collision behaviors Changes needed for / issues found with each emitter:A ...

Physics Constraints do not have the same values if they are part of an 'Always Loaded' level

UE - Gameplay - Dec 3, 2014

Physics Constraints do not have the same values if they are part of an 'Always Loaded' level. They will work correctly in the Persistent level and a level that is Streamed in. This becomes problem ...

FMultiReaderSingleWriterGT isn't thread safe

UE - Foundation - Core - May 17, 2016

From https://udn.unrealengine.com/questions/292741/fmultireadersinglewritergt-isnt-thread-safe.html: I've found that FMultiReaderSingleWriterGT has at least 2 bugs: The one that caused a deadlock ...

Planar Reflections Not Behaving As Expected in Splitscreen

UE - Graphics Features - Dec 19, 2018

This occurs in //UE4/Main @ CL 4670176 Not a Regression. This is similar to https://jira.it.epicgames.net/browse/UE-59149 but when adding more player characters it seems to change the planar reflec ...